The morning this happened, several of us jumped on irc at work to find out exactly what had happened... I was in California at the time, working for Linuxcare, and our Ottawa office gave us the news. When the first plane hit, we thought they were joking. When the second plane hit, we knew this was something serious. We couldn't believe it, but the enormous amount of people in and around the New York and D.C. area taking pictures from their cars, webcams, and other places was astounding.
I collected every image that people were taking and talking about on irc, and for the next few days following, that people were putting on their websites and talking about on irc. I have literally hundreds of photos that have never been published in any media source, ever... including the link in the parent post. There are even close-ups of jumpers, very horrific. Check out the photo series from the guy driving past the Pentagon on the highway..
Some photos are from news sources, and even some people who took pictures of their television sets while the news was on. Unfortunately, the gallery isn't sorted by category.. I just collected them all and put them up for public view. Its been up since a few days after 9/11, and gets a few thousand hits per-day.
http://wtc.sourcefubar.net